Furnace help

[USMC AV8B]

On a short shakedown trip last weekend we had issue with furnace staying lit.
Atwood AFM model. Not sure of number as I have not removed outside access cover yet.
It lites but will go out after about 3 seconds. Lites and goes out 3 times and then has to be reset by turning off and back on. Takes about 3 times resetting before it will stay lit and function properly. After that it will run fine and restart when temp drops below thermostat setting normally!
I did turn on stove and ran that for 30 seconds or so but doesn’t seem to make a difference.
Once it lites and stays lit it functions normal.
Is there a thermocouple on these units that may need cleaning or replaced.
I know I have to clean the one on my home furnace once a year.
This is acting just like my home furnace when thermocouple needs cleaned.
Any thoughts or suggestions on what to try?
I will probably dig into it tomorrow.
It’s on a 2017 Vegas. Atwood AFM furnace.

[LandKO]

Being it was the first outing of the season, it could be something as simple a Air in the line. Once the air is purged, the furnace runs fine.

[16ACE27]

Had it been raining? Sounds like how mine behaves when the circuit board gets wet.

[USMC AV8B]

Originally Posted by 16ACE27

Had it been raining? Sounds like how mine behaves when the circuit board gets wet.

No rain.

[javelin]

Hi, since you ran propane on the stove for a while to purge the lines of air (depending on how those lines are actually run) it sounds like it might be a flame sensor issue. I would suggest opening and inspecting the area around where the flame exists and blow out any dirt, insect nests etc that might be obstructing the flame sensor. Might also need adjusting for flame proximity or replacement perhaps.